Mechanical self-destruct explosive device



Jan. 13, 1970 E. o, UHR|G ET AL MECHANICAL SELF-DESTRUCT EXPLOSIVE DEVTCE 2 Sheets-Sheet 2 Filed Dec. 5l, 1968 F'EE .nll w Awwl. ,I/ "milf Ams :mams:

3,489,107 MECHANICAL SELF-DESTRUCT EXPLOSIVE DEVICE Edward O. Uhrig, Ellicott City, and James C. Hiester, Baltimore, Md., assignors, by mesne assignments, to the United States of America as represented by the Secretary of the Air Force Filed Dec. 31, 1968, Ser. No. 789,057 Int. Ci. G08b 15/00; E05g 3/00 U.S. Cl. 109-36 5 'Claims ABSTRACT F THE DISCLOSURE BACKGROUND OF THE INVENTION This invention relates to a mechanical self-destruct explosive device and, more particularly, to a device which will become active and will self-destruct and, thereby, will destroy an affixed protected package upon the happening of any one of the following contingencies: lapse of a preselected length of time; tampering with the device; and exceeding a force of predetermined magnitude acting along any one of three mutually perpendicular axes of the device.

In the prior art there are numerous devices which employ explosives for destroying, when necessary, a package which is to be protected by said devices. In this connection, it is pertinent here to state that the terms protected package, sensitive package, or the like, are intended to mean and to include, when used herein, anything which is to be protected, and, if necessary, is to be damaged or destroyed, by a destruct-type device which is aflixed, attached, or otherwise linked, directly or remotely, to said protected package. An example of such a protected package, or sensitive package is electronic countermeasures equipment package aboard military aircraft.

As has been previously implied, there are available presently a number of explosive-type self-destruct protective devices which will provide the protection, and cause the destruction, of a sensitive package. Unfortunately, such devices provide protection and cause destruction only under very limited conditions. For example, these devices may require manual initiation. In the case of military aircraft, these devices may require, alternatively, seat ejection. On the other hand, these conventional devices may be made to provide automatic initiation in the event of a hard crash or of a re. However, there is no known explosive-type device which will activate and will self-destruct and, thereby, will cause the destruction of a sensitive package aboard a military aircraft, if the crew members are unable to activate the selfdestruct device and a non-destructive landing (i.e., no hard crash, no fire) is made.

The critical need for a self-destruct device which will self-initiate can only be appreciated when one envisions a highly sophisticated military aircraft carrying a sensitive package aboard, flying over hostile or enemy territory, with the crew members dead or injured (by wounds or otherwise) and, therefore, unable to initiate the activation, directly or indirectly, of the self-destruct device.

'United States Patent O ice Under these circumstances, presently available explosive self-destruct devices initiate or activate only if there is either a hard crash or a tire. It is well known that military aircraft in the circumstances described above have landed without either a hard crash or a fire occurring. Such a non-destructive landing may result in the loss of thesensitive package to unauthorized persons and, if the loss is to a potential enemy or, in fact, to an enemy, the national security of the United States may be jeopardized.

If our invention had been protecting the sensitive packageaboard the aircraft in the above-mentioned circumstances, the sensitive package would have been destroyed, irrespective of the incapacity of the crew members and irrespective of the non-destructive landing.

Therefore, our device fullls a highly critical need in the art and, thereby, advances the state-of-the-art.

In addition, prior art devices are costly, are complex and difficult to manufacture, and require electrical power to energize sensitive electrical circuit components. Our invention eliminates these distinct disadvantages and, therefore, further advances the state-of-the-art.

Although reference has been made to the use of our invention in connection with protecting a sensitive package aboard a military aircraft, it is to be noted that such reference is by way of illustration only, and not by way of limitation. Obviously, our invention may be used whenever and wherever a sensitive package is to be protected.

SUMMARY OF THE INVENTION This invention relates to a mechanical self-destruct explosive device, especially well-suited for use in protecting, and if necessary, destroying sensitive packages, such as electronic countermeasures apparatuses used aboard military aircraft.

An object of this in-vention is to provide a self-destruct explosive device which is highly reliable, but simple to operate, and economical to manufacture.

Another object of this invention is to provide a selfdestruct explosive device which will not require manual initiation, or a hard crash, or a fire to initiate.

Still another object of this invention is to allow selfinitifation of a self-destruct explosive device upon the occurrence of any one or more of the following contingencies: lapse of a preselected length of time; tam-pering with the device; and exceeding a force of predetermined magnitude acting along any one of three mutually perpendicular axes of the device.

A further object of this invention is to provide a selfdestruct explosive device which is wholly mechnaical in operation and does not require any electrical power.

These, and still other, objects of this invention will become readily apparent after a consideration of the description of the invention and reference to the drawings.

DESCRIPTION OF THE DRAWING FIGURE l is a front elevation view of a preferred embodiment of the invention;

FIGURE 2 is a front elevation View of the preferred embodiment shown in FIGURE 1, but with the front plate assembly removed;

FIGURE 3 is a side elevation view of the preferred embodiment, in cross-section, taken along line III- III of FIGURE l;

FIGURE 4 is a cross-sectional view of the preferred embodiment, taken along line IVkIV of FIGURE 3;

FIGURE 5 is a cross-sectional View of the preferred embodiment, taken along line V-V of FIGURE 3; and

FIGURE 6 is a plan View in schematic form of the preferred embodiment, partly fragmented, and of the sensitive package, showing their relative positioning and one 3 means of atlixng the embodiment to the sensitive package.

DESCRIPTION OF THE PREFERRED EMBODIMENT With reference to FIGURE 1, the preferred embodiment includes initiator package with housing 11 and pyrotechnic charge package 60 with housing 61 and,

therein, pyrotechnic charge 62.

The embodiment has ya front cover plate assembly with removable cover 21, a mode selector switch subassembly 22 with switch 23, a window 24, a combination lock subassembly 25 with dial 26, and cover plate fasteners 27.

Cover 21 has openings (i.e., window 24, an opening for switch 23, and an opening for dial 26) and has marked, or preferably engraved, on it legends, numerals, directional arrows, and the like, as shown in FIGURE 1. Three modes are selectable by use of switch 23. These modes are designated, as a matter of preference as: Safe; Time and Tamper Arm; and Tamper Arm. The mode selected appears in window 24. Combination lock subassembly 25 is a three-position, resettable combination lock which seals mode switch 23 and cover plate assembly 20 in place. Cover plate fasteners 27, in conjunction with lock subassembly 25 with dial 26, secures cover 21 to housing 11.

With reference to FIGURE 2, mounting bolts 28 join housing 11 to housing 61. Mounting bolts 29 join housing 11 to the sensitive package to be protected (not shown). Mounting bolts 28 and 29 can be reached only withcover plate assembly 20 removed.

Still with reference to FIGURE 2, indicator mask 30 exhibits in window 24, FIGURE l, the mode selected, in the case of Safe or Tamper Arm. If, however, Time and Tamper is selected, a time to initiate disk 31 appears in windows 24, FIGURE 1, with the preselected length of time being set by rotating or turning time setter 32. When the combination lock 44, FIGURE l, is locked, mode locking pin 33, meshes with notch 34 in mode selector mask drive gear 35, and provides positive locking of the mode selected. Cover interlock pin 36 prevents removal of cover plate assembly 20, FIGURE 1, and, more specifically, of cover 21, FIGURE l, in any position of mode selector switch 23, FIGURE 1, except Safe With reference to FIGURE 3, which is a side elevation view of the preferred embodiment, in cross-section, taken along line III-III of FIGURE l, components shown therein include: cover 21; housing 11; subassembly 22 with mode selector switch 23, shaft 59, shaft shear section 37 which prevents, by shearing, forcible changes of switch 23, cover interlock pin 36 which allows removal of cover 21 only when aligned with the opening in cover interlock housing 38 (i.e., when device is unarmed or Safe), load spring 39, mode locking pin 33 which meshes with locking notch 34 of mode selector mask drive gear 35, and mode selector cam 48. It is to be noted that cover interlock housing 38 is smaller than, to the rear of, and affixed to cover 21 with the rear of cover 21 serving as the front of housing 38.

Components which are also shown in FIGURE 3, include: indicator mask 30; time to initiate disk 31; mask drive gear 41; cover lock slots 42; pins 43 which are seated by action of rotatable dial 26 of resettable, combination lock 44 of combination lock subassembly 25 and cover lock 45; spring driven timer mechanism 46; load spring 47; triggering cam surface 49; firing hammer latch tiring hammer 50; and force G1 of predetermined magnitude with an arrow showing its direction.

With reference to FIGURE 4, which is a cross-sectional view of the preferred embodiment, taken along line IV-IV of FIGURE 3, the components shown therein include: tiring hammer latch 40; load spring 47; timer pawl 58, tiring hammer 50; tiring pin 51 which detonates tiring cap 52; firing pin cushion 53 which prevents ring cap 52 from detonating, except when firing hammer 50 is trigger by the occurrence of any one of the prescribed contingencies; tiring hammer spring 54; access port 55 which allows firing hammer 50 to be set or reset; 'and forces G2 and G3 (which are mutually perpendicular and perpendicular to force G1, FIGURE 3) of predetermined magnitude with arrows showing their respective direction.

With reference to FIGURE 5, which is a cross-sectional view of the preferred embodiment, taken along line V-V of FIGURE 3, the components shown therein include: cam surface 56 on mode selector switch subassembly 22; cam surface 57 on mode selector switch subassembly 22; triggering cam surface 49; firing hammer latch 40; time setter 32; timer pawl 58; and mounting bolts 29.

With reference to FIGURE 6, which is a plan view in schematic form of the preferred embodiment, partly fragmented, and of the sensitive package, showing their relative assembled position and one means of affixing the embodiment to the sensitive package, the components shown there include: initiate package 10 with housing 11, front cover 21, and mounting bolts 28 and 29; pyrotechnic charge package 60 with housing 61 and, therein, pyrotechnic charge 62; and sensitive package 70 with housing 71 and mounting base 72. Also shown 'are independent mounting base 73 and bolts 74.

MODE OF OPERATION OF THE PREFERRED EMBODIMENT The initiator component 10 of our mechanical selfdestruct explosive device will actuate, causing the explosion of pyrotechnic package 60, if any of the following contingencies occur: lapse of the preselected time; tampering with the self-destruct device; and exceeding a force of predetermined magnitude (G1, FIGURE 3; G2 and G3, FIGURE 4) acting along, and in the direction of, any one of three mutually perpendicular axes (i.e., arrows in FIGURES 3 and 4) of the self-destruct device.

In essence, explosion by lapse of preselected time iu controlled by, and caused by, spring driven timer mechanism 46, FIGURE 3, and associated co-operating components; explosion by tampering is controlled by, and caused by, attempting to remove cover 21, FIGURES l, 3 and 5, or cover plate subassembly 22, FIGURES l and 3, from housing 11, FIGURES 1, 3 and 5, or -by forwardly moving spring Stressed shaft 59, FIGURE '3, with or without using mode selector switch 23, FIGURES 1 and 3, with any of such 'actions or attempts taking place when the self-destruct device is armed; and explosion by exceeding a force of predetermined magnitude is controlled by, and caused by: load spring 39, FIGURE 3, tiring hammer latch 40, FIGURES 3, 4 and 5, and associated co-operating components as to force G1, FIGURE 3; load spring 47, FIGURES 3 and 4, and associated cooperating components as to force G2, FIGURE 4; and by tiring pin 51, FIGURE 4, and associated co-operating components las to force G3, FIGURE 4.

More specifically, explosion by lapse of preselected time (i.e., time trigger action) is provided by setting the desired length of time by rotating time setter 32, FIGURE 2, which, additionally, winds spring driven timer mechanism 46, FIGURE 3. The remaining time to initiate is shown on suitably marked disk 31, FIGURES 2 and 3, which, linked with timer mechanism 46, FIGURE 3, rotates uniformly with the lapse of time. When the preselected length of time has elapsed or passed, timer pawl 58, FIGURES 4 and 5, which is linked with rotatable disk 31, FIGURES 2 and 3, and spring driven timer mechanism 46, FIGURE 3, and time setter 32, FIGURE 2, trips firing hammer latch 40, FIGURES 3, 4 and 5, by depressing load spring 47, FIGURES 3 and 4, and permitting compressed firing hammer spring 54, FIGURE 4, to expand, thereby forcing tiring hammer 50, FIG- URES 3 and 4, forward, with the result that hammer 50 strikes firing pin 51, FIGURE 4, detonating firing cap 52, FIGURE 4, exploding pyrotechnic charge 62, FIG- URES 1 through 5.

Initiation by tampering is provided by the sequential action of co-operating components when the device is in an armed mode and an attempt is made to -remove cover 21, FIGURES 1, 3 and 5, or cover plate subassembly 22, FIGURES l and 3, from housing 11, FIGURES 1, 3 and 5, or by forwardly moving spring stressed shaft 59, FIGURE 3, with or without using mode selector switch 23, FIGURES l and 3. When any of these tampering actions take place, shaft 59, FIGURE 3, is moved forward and, as a result, cam 48, FIGURE 3, which is perpendicularly aixed to one end of shaft 59, FIGURE 3, is moved or pulled forward. When this occurs, triggering cam surface 49, FIGURES 3 and 5, which is slideably in contact with the inner surface of Ifiring hammer latch 40, FIGURES 3, 4 and 5, moves or trips firing hammer latch 40, FIGURES 3, 4 and 5, which allows the release of spring stressed firing hammer 50, FIGURES 3 and 4. Hammer 50 is forced forward by the expansion of compressed spring 54, FIGURE 4, with the result that hammer 50 strikes firing pin 51, FIGURE 4, detonates firing cap 52, FIGURE 4, and thus explodes pyrotechnic charge 62, FIGURES l through 5.

Explosion by exceeding a force of predetermined magnitude along any one of three mutually perpendicular axes of the device is provided by any one of the following: (a) load spring 39, FIGURE 3, is compressed when a force in excess of G1, FIGURE 3, is applied in the direction of, and along, the axis designated by the arrow in said FIGURE 3, resulting in movement of firing hammer latch 40, FIGURES 3, 4 and 5, and, after sequential action of cooperating components, explosion of pyrotechnic charge 62, FIGURES 1 through 5; (b) load spring 47, FIGURES 3 and 4, is compressed when a force in excess of G2, FIGURE 4, is applied in the direction of, and along, the axis designated by the arrow in said FIGURE 4 (near designation of force G2), resulting in tripping firing hammer latch 40, FIGURES 3, 4 and 5, permitting compressed firing hammer spring 54, FIGURE 4, to expand, moving firing hammer 50, FIG- URES 3 and 4, forward, striking firing pin 51, FIGURE 4, detonating firing cap 52, FIGURE 4, and exploding pyrotechnic charge 62, FIGURES l and 6; (c) firing pin 51, FIGURE 4, will move forward and strike detonating tiring cap S2, FIGURE 4, exploding pyrotechnic charge 62, FIGURES 1 and 6, when a force in exess of force G3, FIGURE 4, is applied in the direction of, and along, the axis designated by the arrow in said FIGURE 4 (near designation of force G3).

If the device is to be used to protect a sensitive package aboard a military aircraft about to become airborne, it is preferred that prior to take-olf the device be armed -by an authorized person who will not be aboard the aircraft in flight, who knows the operation of the device, and who knows, or is able to set, the combination of resettable combination lock 44, FIGURE 3, of combination lock subassembly 25, FIGURES l and 3.

Although three modes (i.e., Safe, Time and Tamper Arm, and Tamper Arm) are selectable by rotation of mode selector switch 23, FIGURES 1 and 3, it is assumed, in view of the above circumstances that the device is in the Safe mode. It is here to be noted that if a person, other than a person who knows the combination of lock 44, FIGURE 3, attempts to tamper with the mode selector switch 23, FIGURES 1 and 3, the shaft, of which switch 23 is an integral part, will shear at shaft shear section 37, FIGURE 3, thereby preventing forcible switch 23 position change and undesired arming Subsequent explosion. The device will remain in a Safe mode and will not explode.

An authorized person setting the device follows the following procedure:

If he desires to set the device in the Time and Tamper Arm mode, he unlocks the device by rotating dial 26, FIGURES 1 and 3, using the combination of lock 44, FIGURE 3. He removes the cover plate assembly 20, which includes cover 21, and he sets or winds time setter 32, FIGURES 2 and 5. He then returns cover plate assembly 20 to its proper position on the device; selects the Time and Tamper Arm mode by using mode selector switch 23, FIGURES 1 and 3; and locks combination lock 44, FIGURE 3, by rotating dial 26, FIGURES 1 and 2. When the device has ybeen set for Time and Tamper Arm action, cam surface 56, FIGURE 5, allows the release of timer pawl 58, FIGURES 4 and 5, for time count down; and, cam surface 57 allows clearance for firing hammer latch 40, FIGURES 3, 4 and 5, so that tampering with the device or exceeding a force of a predetermined magnitude acting along, and in the direction of, any one of the three mutually perpendicular axes of the device, such as force G2, FIGURE 4, will initiate and explode the device and sensitive package 70, FIGURE 6.

The authorized person unlocks the device by rotating dial 26, FIGURES 1 and 3, using the combination of lock 44, FIGURE 3, and removes cover plate assembly 20, which includes cover 21. He then sets the device to either the Time and Tamper mode or to the Tamper Arm mode by using mode selector switch 23, FIG- URES 1 and 3, which is now movable, because of the unlocking of combination lock 44, FIGURE 3, and the removal of cover plate assembly 20. If he selects the Time and Tamper Arm mode, he sets or winds time setter 32, FIGURES 2 and 5. If he selects the Tamper Arm mode, such action is, of course, not necessary. After selecting either mode, he then returns cover plate assembly 20 to its proper position and locks combination lock 44, FIGURE 3, by rotating dial 26, FIGURES 1 and 2.

If the Time and Tamper Arm mode is selected, cam surface 56, FIGURE 5, allows the release of timer pawl 58, FIGURES 4 and 5; time count down; and resultant explosion, when there is the lapse of the preselected time or tampering with the device or the exceeding of a force of predetermined magnitude acting along, and in the direction, of any one of the three mutually perpendicular axes of the device.

If he desires to set the'device in the Tamper Arm mode, he unlocks the device by rotating dial 26, FIG- URES 1 and 3, using the combination of lock 44, FIG- URE 3. Removal of cover plate assembly 20 is not necessary. He then sets the Tamper Arm mode by using mode selector switch 23, FIGURES l and 3; and he locks combination lock 44, FIGURE 3, by rotating dial 26, FIGURES 1 and 2. When the device has been set for Tamper Arm action, cam surface 57, FIGURE 5, moves in response to tampering, releasing firing hammer latch 40, FIGURES 3, 4 and 5, Which allows the firing hammer 50, VFIGURES 3 and 4, to strike the ring pin 51, FIGURE 4, with a resultant explosion. An explosion will also occur if, without tampering, there is the exceeding of a force of predetermined magnitude acting along, and in the direction of, any one of the ythree mutually perpendicular axes of the device. For example, cam surface 56 allows clearance for ring hammer latch 40, FIGURES 3, 4 and 5, so that a force exceeding the magnitude, and acting along the direction, of force G2, FIGURE 4, will allow detonation.

The term force, as used herein, is intended to include a force that is caused by an acceleration exceeding a threshold of predetermined shock magnitude, such as hammering on the device, crash of aircraft, or the like.

While there has been shown and described the fundamental features of our invention, as applied to a preferred embodiment, it is to be understood that various substitutions and omissions may be made by those skilled in the art, without departing from the spirit of the invention. For example: Although initiation has been described exclusively using mechanical components, such as a firing hammer and a firing pin, initiation by the interaction of mechanical components is for illustrative purposes solely, rather than as a limitation. Obviously, means for causing initiation need not be exclusively mechanical. Initiation may be caused, for example, by means making use of the piezo-electric effect, or by the actuation of an electrical or magnetic operated switching circuit, and the like.

What we claim is: 1. A mechanical self-destruct explosive device, com

prising:

(a) a first housing;

(b) means, contained within said first housing, for

initiatingV the explosion of a pyrotechnic charge;

(c) a second housing affixed to said first housing;

(d) a pyrotechnic charge contained within said second housing;l

(e) and, a third housing, affixed to said first housing and said second housing, for containing an item to be protected.

2. A device, as set forth in claim 1, wherein said means, contained within said first housing, for initiating the explosion of the pyrotechnic charge, includes:

for initiating the explosion of the pyrotechnic charge when there is a lapse of a preselected length of time, includes:

(a) a spring driven timer mechanism;

(b) a time setter, linked to said spring driven timer mechanism, to wind said timer and to select a length of running time;

(c) a rotatable disk, linked to said spring driven timer mechanism and said time setting, rotating uniformly with the lapse of time and suitably marked to indicate time remaining to initiation;

(d) a timer pawl, linked to said spring driven timer mechanism and said time setter and said rotatable disk;

( e) a load spring abutted by said timer pawl and compressed by said timer pawl 4when the preselected length of time to initiation has elapsed;

(f) a firing hammer latch, linked to said load spring, and tripped by said load spring when said load spring is compressed by said timer pawl;

(g) a spring stressed firing hammer, linked to said firing hammer latch, and forced forward by said stressed spring when said firing hammer latch is tripped by said load spring;

(h) 4a firing pin, suitably disposed with relation to said spring stressed firing hammer so as to be struck by said firing hammer when said firing hammer is forced forward by said stressed spring;

(i) and, a detonating type firing cap in close proximity to the pyrotechnic charge and suitably disposed in relation to said firing pin so as to be struck by said firing pin when said firing pin is struck by said firing hammer, with resultant detonation of said firing cap and explosion of said pyrotechnic charge.

4. A device, as set forth in claim 2, wherein said means for initiating the explosion of the pyrotechnic charge when there is tampering with the device, includes:

(a) a removable, externally lockable cover for the device having an opening, and locked onto the device;

(b) a spring biased shaft having a pin transversely set in and protruding from either side of one end of said shaft, with said shaft positioned approximately perpendicular to said cover and with said end of said shaft fitted into the opening in said cover;

(c) a housing, smaller than said cover and affixed to the rear thereof, with the rear of said cover serving as the front of said housing, and with said housing having an opening through said pinned end of said shaft is inserted and rotated to prevent the retraction of said pinned end;

(d) a cam disposed to the rear of said housing and afiixed perpendicularly to said shaft near the end of said shaft which is not pinned;

(e) a firing hammer latch, the inner surface of which is slideably in contact with the outer periphery of said cam, which is tripped when said cam is moved forward by the forward movement of said shaft caused by forcible forward movement of said cover;

(f) a spring stressed firing hammer, linked to said firing hammer latch, forced forward by said stressed spring when said firing hammer latch is tripped by the forward movement of said cam;

(g) a firing pin, suitably disposed with relation to said spring stressed firing hammer so as to be struck by said firing hammer when said firing hammer is forced forward by said stressed spring;

(h) and, a detonating type firing cap in close proximity to the pyrotechnic charge and suitably disposed in relation to said firing pin so as to be struck by said firing pin when said firing pin is struck by said firing hammer, with resultant detonation of said firing cap and explosion of said pyrotechnic charge.

5. A device as set forth in claim 2, wherein said means for initiating the explosion of the pyrotechnic charge when a force acting along, and in the direction of, any one of three mutually perpendicular axes of the device, exceeds a force of predetermined magnitude, comprising:

(a) a first load spring which is compressed when a force of predetermined magnitude is applied;

(b) a firing hammer latch, to which said first load spring is linked, which is tripped by the compression of said first load spring;

(c) a second load spring, perpendicular to said first load spring and linked to said firing hammer latch, with said second load spring being compressed when a force of predetermined magnitude is applied, tripping said'firing hammer latch;

(d) a spring stressed firing hammer, linked to said firing hammer latch and forced foward by the stressed spring when said firing hammer latch is tripped;

(e) a firing pin, perpendicular to said first load spring and said second load spring, which responds by forward movement to a force of predetermined magnitude, and is suitably disposed so as to be struck by said firing hammer and is moved forward when said firing hammer is forced forward by said firing pin;

(f and, a detonating type firing cap, in close proximity to the pyrotechnic charge and suitably disposed in relation to said firing pin so as to be struck by said firing pin when said firing pin is moved forward, with resultant detonation of said firing cap and explosion of said pyrotechnic charge.

References Cited UNITED STATES PATENTS 645,135 3/1900 Scalona IGZ-37.3 1,454,894 5/1923 `lohnson 109-36 2,384,826 9/1945 Ferguson 109-29 X 3,053,416 9/ 1962 Harner 109-36 X J. KARL BELL, Primary Examiner 

